1. Field of the Invention
This invention relates to glass technology, and particularly to a method and apparatus for cutting sheets of laminated glass having a resilient intermediate layer.
2. Description of the Prior Art
The prior art relating to this invention is believed contained in Class 83, sub-classes 879, 883, 884, 885, 455, 489, 485, and 665; and Class 33, sub-class 32; and Class 30, sub classes 286, 287, 289, 290, 292 and 294.
A search through this field of search has revealed the existence of six patents as follows: U.S. Pat. Nos. 2,273,716 2,058,092 2,964,848 2,750,674 2,706,002 3,127,680
While five of the above patents relate to the cutting of glass, none of these five patents relate to the problems created in cutting a pane of "safety" or laminated glass so that the two panes of glass that make up the lamination may be separated so as to expose the intermediate resilient plastic sheet material. The sixth patent, U.S. Pat. No. 2,706,002, relates to the cutting of building materials, such as sheet rock or wall board, which is a product that utilizes a matrix of frangible plaster interposed between and adhesively secured to two layers of pressed fibrous paper. This patent discloses an apparatus for cutting through the two surface layers of fibrous paper so that the intermediate frangible matrix may then be cracked so as to separate one part from another. This construction and mode of operation is of course different from that proposed in or by the present invention.
Conventionally, a pane of glass is cut by scoring a line across the pane of glass and then imposing stress in the region of the score line so as to cause the pane of glass to crack along the score line so that one piece may be separated from the other piece on the opposite side of the score line. This procedure is adequate for a pane of glass that is of a single thickness. However, this procedure is not sufficient for glass that constitutes a lamination of two panes or lights of glass having laminated therebetween a layer of a resilient plastic material adhesively secured to the two facing surfaces of the two panes of glass. If a conventional method and apparatus. is used to cut "safety" or laminated glass, a first score line has to be made on one of the two panes of glass. Then, the entire double-pane assembly must be turned over so that the opposite side of the pane of glass may be scored. The conventional procedure is then followed to cause each of the panes of glass to crack along the scorelines. Even after cracking, this still leaves the pane intact in that the intermediate layer of resilient plastic material has not been cut and the separate glass portions may not be separated. Additionally, this method poses a problem because after one layer of glass has been scored, it is difficult to turn the entire double-pane assembly of glass over to score the opposite side because the scored portion may crack, thus imposing undue stress on the remaining pane of the laminated pair of panes. This imposition of stress imposed on the remaining pane prior to its scoring operation, tends to cause breakage of the pane. Accordingly, it is one of the principal objects of this invention to provide a method and apparatus for scoring both sides of the laminated double-pane simultaneously so that the entire pane assembly need not be turned over after the scoring operation.
Another object of the invention is the provision of means for imposing stress on the two score lines in the two laminated panes so as to crack both laminated panes of glass without the necessity of turning the sheet of glass over to reverse its attitude on the table.
Another object of the invention is the provision of apparatus which will retain the glass elevated above the table top so as to permit both sides of the laminated pane of glass to be scored simultaneously.
Still another object of the invention is the provision of apparatus which is relatively simple to manufacture, thus being economical and within the reach of most glass shops, and which is relatively simple to manipulate so as to eliminate the necessity of hiring experienced or skilled operators.
The glass industry has been at a disadvantage because laminated panes of glass of large size are too cumbersome for a single individual to manipulate. In fact, the industry has limited to 7'.times.10' the size of laminated glass panes that are manufactured because of such difficulty in handling. Accordingly, it is still another object of the invention to provide a glass cutting apparatus and method that will permit the industry to manufacture laminated panes of glass in sizes much larger than is usual, and which will enable a single individual to manipulate the larger glass panes and cut smaller panes of glass from the large pane, thus making more economical the manufacture and shipment of laminated glass panes.
The invention possesses other objects and features of advantage, some of which, with the foregoing, will be apparent from the following description and the drawings. It is to be understood however that the invention is not limited to the embodiment illustrated and described, since it may be embodied in various forms within the scope of the appended claims.